1. Field of the Invention
The invention relates generally to hygienic compositions of matter useful particularly as dentifrices which also exhibit germicidal activity.
2. Description of the Prior Art
Dentifrice compositions have long been employed which contain therapeutic and prophylactic agents intended to destroy bacteria which find highly favorable growth conditions in accumulated food particles which lodge between the teeth and in the plaque film which forms on the surfaces of the teeth. Such compositions have often been mixed with abrasives to provide the compositions normally referred to as dentifrices. Similar compositions which do not contain abrasives and which are usually referred to as hygienic compositions or "mouth washes" are particulary used to create antiseptic conditions in the mouth by destruction of bacteria either directly and/or by facilitating the removal of food particles and/or plaque film on which bacteria thrive. The oral hygienic compositions often contain ingredients which are astringent in order that the mucous membrane can be shrunk or which are effective for desensitizing the teeth. In order to be acceptable for these uses, dentifrice and oral hygiene compositions (which will be hereinafter referred to interchangeably) must not harm sensitive oral tissues, must not react unfavorably with the teeth, and must not be harmful if swallowed. Many powerful oxidizing agents, such as those which strongly liberate chlorine, are thus unsuited for use in the dental care environment.
The prior art has provided compositions, even chlorine-liberating compositions, which have proven useful at least to some degree. In particular, Resnik, in U.S. Pat. No. 1,435,498, provides a dentifrice comprised of a hypoclorite chlorine-releasing agent. Omohundro, in U.S. Pat. No. 2,317,297, teaches the use of active oxygen-releasing agents in a dentifrice, the agents releasing either hydrogen peroxide as an intermediate or oxygen immediately upon use.
Mouth washes have also been long available which use zinc chloride as an antiseptic and astringent agent and which is intended to promote the healing of wounds and also to desensitize the teeth. As is thus apparent, hydrogen peroxide and zinc chloride have long been used separately as therapeutic agents which at least incidentally exhibit germicidal activity. Hydrogen peroxide owes germicidal activity to oxygen release which, due to the kinetics of the release, provides a mechanical as well as a chemical mechanism for cleansing wounds and also for removing tissue and other debris from inaccessible areas such as from between the teeth. The oxygen release of hydrogen peroxide is particularly pronounced in the presence of organic matter, reducing agents, metals, and metal salts. Since zinc chloride is also an effective germicidal agent, a combination of hydrogen peroxide with zinc chloride would hold promise as an effective germicidal combination which would particularly be effective as a hygienic dentifrice composition. However, combinations of hydrogen peroxide and zinc chloride have not been generally utilized due to the fact that hydrogen peroxide, as indicated above, liberates oxygen in the presence of metal salts. Accordingly, solutions of hydrogen peroxide to which zinc chloride has been added have been inherently unstable, oxygen release occurring within a time period which is sufficiently short as to render the shelf life of the mixture unacceptable. While hydrogen peroxide or zinc chloride have at times been mixed immediately prior to use, especially in the clinical environment, in order to obtain those benefits previously alluded to, this desirable combination of hygienic germicidal agents has not come into general clinical use and is effectively unavailable for general public use due to the instability of the mixture.
Various stabilizing agents have been proposed for extending the shelf life of a hydrogen peroxide/zinc chloride mixture. These agents have proven essentially worthless due to the fact that certain of the agents have been ineffective in preventing hydrogen peroxide decomposition, that is, oxygen release, while other stabilizing agents have actually stabilized the mixture to such a degree that the effectiveness of the mixture is impaired due to a reduced oxygen release. The present invention provides a stabilized hydrogen peroxide hygienic composition which also exhibits the additional antiseptic, healing, and desensitizing benefits obtained from the use of zinc chloride. In particular, the present invention provides a composition of matter containing both hydrogen peroxide and zinc chloride, which composition of matter is stabilized by the addition of water soluble vitamin E to the extent that the composition has an acceptable useful shelf life and is still sufficiently active to release oxygen on contact with organic matter such as occurs when the composition is utilized as an oral hygienic solution. The present invention therefore provides a useful oral hygienic composition of matter which avoids the problems encountered in the previous use of solutions containing both hydrogen peroxide and metal salts such as zinc chloride.